Electric circuit breaker



April 28, 1953 H N, sCHNElDER 2,636,961

ELECTRIC CIRCUIT BREAKER Filed Nov. 9, 1951 Invenbvw, Harold N.Schneiden,

mma/d@ His Attorneg.

Patented Apr. 28, 1953 ELECTRIC CIRCUIT BREAKER Harold N. Schneider,Springfield, Pa., assignor to' General Electric Company, a corporationof NewYorkv Application November 9, 1951; Serial No. 255,696

(ci. zooliisf 8 Claims; 1

This invention relates to electric circuit breakers and moreparticularly to circuit breakers of the huid-blast type whereincurrent-interrupting contacts are arranged in series relation tocircuit-isolating contacts which are opened subsequent to the opening ofthe interrupting contacts. In circuit breakers of this type, a. resistoris frequently connected in parallel with the interrupting contactssothat the resistor current which flows after opening `of theinterrupting contacts must be interrupted by the isolating contacts. i y

Application Serial No. 2Gl,96l, of AAlbert Roxburgh et al., iiledDecember` 2 1, 1950, and application Serial No. 202,100,0f John W.Beatty, iiled December 21-, 1950,whichare assigned to the assigneeofthisinventionboth disclose and claim interrupters whereininterruptingcontacts are connected in series withisolating contacts and whereinaresistor is connected in parallel with the interrupting contacts. Boththe Roxburgh et al. and the Beatty applications are of the airblasttype. Furthermore, both these applications disclose arrangementsVwherein three exhaust passages are provided for the removal of pressuregas supplied tothe interrupter. y p l Aprincipal object of thisinvention-is to pro- Vide an improved iluid blastjcircuit breaker'whichis simple, compact and rugged in construction.

Another object of this invention isthe provision of an improved gasblastcircuit'break'er which is arrangedwith ammi-mum of'exhaust passagesfor the'dischargeo-gas to Yatmosphere so as to obtain optimum use ofthepressure-gas without causing wastage thereof.

Still another object of this'invention is to -provide a gas blastcircuit vbreaker-wherein ablast of gas supplied to the breaker mayreadily exhaust to atmosphere during aY circuit-interrupting operationthrough a pluralityof exhaust vpassages, and through at least one lessexhaust passage after interruption ofthe circuit,lfthe reby toenhancethe `conservation ofy pressure E gas.l

A -further object of this invention is the-provision of agas blastcircuit breakerwhereinall parts are arranged inline-and Iwith alllthe-contact members contained within a-single compact enclosingstructure.

The invention in one' form as applied toa gas blast circuitbreakercomprises an enclosing structure in which is disposed Va tubularconducting member havingan interruptingcontact normally in engagementwith oneend Athereof and having y a tubular isolating contact disposedin substantially` coaxial relation thereto `at the other Ving tubularmember i.

4toward engagement with the upper end of a fixed end thereof. Bridgingcontact means may be arranged'normally to interconnect the conductingmember electrically and also pneumatically with the tubular isolatingcontact so that these parts forman exhaust path for pressure gassupplied to the of the conducting member remote from the Visf'llatingcontact during the operationof the interrupting contact. ln'addition,iuid pressure responsive means may be vused to cause the bridgingcontact' means to operate after operation of the interrupting contactmeans so as to isolate the circuit and to prevent the exhaust of fluidthrough the tubular conducting member thereby to conserve the supply oipressure gas.

The' invention both as toits organization and method of operationwillbebetter understood from the following description taken in connectionwith the accompanying drawing in which thesingle iigure thereof is across-sectional view showing'av circuit breaker embodying the principlesof the invention.

In" the drawing, the numeral l represents a tiibi'ilarv insulatingcasing iorming a portion'of the enclosingstructure or the circuitbreaker. The tubular member l is mounted on suitable base structure lacomparable to that shown and describedin the above-mentioned Beattyapplication Serial No. 202,106." The base structure la is provided with.a chamber lb which permits upward incoming blasts of gasoutside thechamber Iband'which forms' a downward exhaust path inside the chamber,both being indicated by arrows in'thedrawing. Secured to the upper endof tubular enclosing structure E is a metallic support member 2. Member'2 is aliixed to tubular'in'sulating member i by means of bolts 3 whicheng'ageclamping ring l which in turn forces the wedge-shaped segments 5into gripping relation with the upper end 'of insulating enclos- Mountedon the support member il is a closure cap member 6 which is secured toymember 2 by bolts which extend through sleeves il. Secured to the top'surface of the'cover 6 is an insulating plate El and mounted'within themember c is a foraminated wall l which `acts in known marier to cool theproducts of an interrupting operation before the exhaust thereof in thedirection of the arrows to atmosphere through the passage generallydesignated by the numeral l l.

Disposed within the support structure j a plurality of finger contactsi2 which are fiilcrumed at E3 to the base member 2 and whie are'bias'edby'rn'e'ansv ef compressional springs l tubular conducting member i5which is mounted within the insulating enclosing structure I by means ofdevices such as are indicated at Ita. A more detailed disclosure of theparticular arrangement of the petal-type contacts I2 and partsassociated therewith is set forth in application Serial No. 233,637, ofJohn W. Beatty, filed June 26, 1951. The contacts I2 are moved out ofengagement with the nxed tubular conducting member I5 by means of ablast of gas, such as air under pressure, which is supplied to the basestructure Ia by any suitable valve means such as is disclosed inapplication Serial No. 233,542, of Ronald B. Shores, filed June 26,1951, and assigned to the assignee of this application.

Connected between the support structure 2 and the member Iba, which isin electrical contact with the fixed tubular conducting member I5, is ashunt resistor I6. Thus it will be seen that once the finger contacts I2are separated from the xed conducting member I5, a portion of thecurrent through the circuit breaker fiows through the resistor It. Afterinterruption of the arc, the current through the resistor must beinterrupted by other means. As in the abovementioned Roxburgh et al.application, this resistor current is interrupted by means of a socalledisolating contact.

In the drawing, a suitable isolating contact is indicated by the numeralI'I. Disposed for cooperation with the isolating contact Il is a slidingcontact or other suitable connecting means such as indicatedschematically at I3 while a terminal I9 is provided on the supportstructure 2. Electrical contact between isolating contact Il andstructure I5 is normally maintained by the bridging contacts 2&3. Thusthe circuit through the interrupter comprises the terminal I9, member 2,finger contacts I2, fixed tubular conducting member E5, the bridgingcontacts 2G and the isolating contact I'I and the terminal I8. Thecurrent through resistor It is interrupted by the action of theisolating contact I1 separating from the bridging contacts 2t after theinterruption of the arc drawn by the contacts I2. To this end thecontacts 2@ are disposed within a cradle-like piston member 2l and arebiased toward engagement with the conducting member I5 and the isolatingcontact Il by individual compressional springs 22. member 2I is operablewithin the cylindrical structure 23 and suitable bias for the piston 2|is provided in the form of a plurality of compressional springs 2d whichare disposed about a plurality of guide rods 25 and which effectivelybias the piston member 2I downwardly, the springs 2li being inengagement at their lower ends with a projecting shoulder 26 secured tothe guide rods 25.

In order to control the upward movement of the piston member EI andparts associated therewith in such a way as to insure the separation ofbridging contacts 2&3 from isolating contact I'I after interruption ofthe arc by the interrupting contacts I2, a suitable port 2l is providedin the cylinder wall 23 and a needle valve 23 is provided in theterminal member Iba. Thus when a blast of pressure fluid is supplied tothe space between the insulating sleeve I and the isolating contact Il,the upward movement of piston member 2| is delayed sufficiently so thatcontacts 20 separate from isolating contact il after separation ofinterrupting contacts I2 from the tubular conducting member I5. Theeffect of port 2'! is to precharge with pressure fluid the Thecradle-like piston space above the piston 2|, which fluid opposes theimmediate formation of the isolating gap while the operation of needlevalve 28 is such as to regulate the exhaust of pressure fluid from thespace above piston 2i at a controlled rate for determining the timedelay between interrupting and isolating. After, or coincident with,interruption of the resistor current by means of the contacts 2t, theisolating contact Il is moved downwardly. The particular apparatus forcausing downward movement of contact is not shown in the drawing sincesuch apparatus forms no part of the present invention. Suitableapparatus for this purpose is disclosed in the abovementionedapplication of Ronald B. Shores.

In View of the above description, it will be understood that, whenpressure gas is supplied to the lower portion of tubular insulatingmember I in the space between that insulator and the isolating ContactIl, such pressure gas flows upwardly nrst to separate the interruptingcontacts I2 from the fixed tubular contact I5 before the isolatingcontact Il' is drawn downwardly. Such pressure gas is exhausted upwardlythrough the cover member t and the opening I I in the direction of thearrows 23 and also flows downwardly through the tubular conductingmember I5 in the direction of the dotted-line arrows 3D. The downwardlyowing exhaust gas in tubular conducting member I5 iiows on through thespace between the conducting member I5 and the isolating contact Il',thereafter through the isolating contact Il and to atmosphere throughthe ports 3d in base member Ia. Thus during this interrupting process,the pressure uid flows both upwardly and downwardly from the regionsurrounding the interrupting contacts I2. After the cradle-like piston2i is moved upwardly so as to separate the contacts 2S from theisolating contacts I'I, the pressure from the source can flow into thespace between the lower end of conducting member I5 and the upper end ofisolating contact I I so as to oppose the flow of uid downwardly throughthe conducting member I5 from the interrupting contacts I2.

Accordingly, this new influx of blast pressure through the insolatinggap will oppose or neutralize the downward exhaust flow through thefixed tube I5 from the main contact arc gap. More specifically, thedownward exhaust flow represented by arrows 3 will be effectivelyopposed by the upward component of the isolating gap blast indicated byarrows 32 while the downward component of the gap blast represented bythe arrows 3l follows the original exhaust path to atmosphere throughthe presently downwardly moving isolating tubular contact I1, which, inthe next instant, may be assumed to be passing through a point in itsopening movement represented by the dotted transient position 33.

Thus it will be seen from the above description that by the invention asubstantial blast of gas is supplied to the interrupting contacts I2during the interrupting operation due to the fact that two exhaust pathsare provided; i. e., upwardly in the direction of the solid line arrows23 and downwardly in the direction of the dotted line arrows 30. Afterthe main arc is extinguished, the blast to the interrupting contacts I2need no longer be high in magnitude. Thus this blast is reduced due tothe fact that incoming pressure gas indicated by the arrows 32 iiowsthrough the space between the isolating contact Il and the xedconducting member I5 to encounter the fluid tending to ow downwardly inconducting member I5 in the direction of the dotted line arrows 30. Thusthe pressure across the ends of the xed conducting member l5 becomessubstantially equalized to render ineffective one exhaust path and toreduce the total blast to the interrupting contacts. In this way, asubstantial amount of pressure gas is conserved.

It will also be understood that by the invention, a compact and ruggedarrangement is possible and that all the parts may be mounted in line ina single columnar structure which occupies a minimum of space.

Although the chosen embodiment described herein has featured aretracting isolating contact with pneumatic timing as constituted by thepiston-carried contacts 2G; it will be understood that the movableisolating contact could abut, or telescope with, or engage tulip-typecontacts mounted upon, the lower end of the xed tubular conductingmember I5. In such a case, the opening instant of the isolating gapwould be accomplished by mechanically timing the downward openingmovement of the moving tubular contact I1.

From the above detailed explanation it will be appreciated that theinvention essentially provides a continuous substantially open-ended,tubular, current-carrying structure which is made disjointable at twospaced points along its length to constitute a pair of series breaks. Byenclosing these breaks in a common pressure-conning casing, and byarranging for the sequential opening of the breaks, the gas blastintroduced to the `casing produces a double-exhaust arc-extinguishingblast at the break toward one end of the structure which, coincidentywith the opening of the other break, becomes limited to asingle-exhaust scavenging blast.

While I have shown and described a particular embodiment of theinvention, I do not wish to be limited thereto and intend in theappended claims to cover all such changes and modifications as fallwithin the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. An electric circuit breaker of the duid-blast type comprising anenclosing structure, a plurality of hollow tubular conducting elementsnormally arranged in series conducting relation with each other and`defining a continuous hollow passage the extremities of which form uidexhaust passages, said elements being relatively movable during acircuit-opening operation so as to establish two gaps in sequence, saidenclosing structure being arranged with respect to said conductingelements so as to enclose said gaps, and means for supplying a blast offluid pressure to said structure, said fluid being exhausted in bothdirections through said hollow passage from the rst of said gaps to beestablished during a circuit-opening operation prior to theestablishment of the second of said gaps, fluid pressure supplied tosaid second gap being in opposition to the flow of fluid through saidhollow passage from the rst of said gaps to be formed to the second ofsaid gaps to be formed.

2. An electric circuit breaker of the duid-blast type comprising anenclosing structure, a plurality of hollow tubular conducting elementsnormally arranged in series conducting relation with each other anddefining a continuous hollow passage the extremities of which form fluidexhaust passages, said elements being relatively movable during acircuit-opening operation so as to establish two gaps in sequence, saidenclosing struc- 6 ture being arranged with respect to seid conductingelements so as to enclose said sans, and means for supplying a blast offluid pressure to said structure, the fluid pressure Supplied to thesecond of said gaps to be formed being in opposition to the flow offluid from the first of said gaps to be formed through said hollowpassage toward the said second of said gaps.

3. An electric circuit breaker of the fluidblast type comprising anenclosing structure, a xed tubular conducting member disposed withinsaid structure, a movable tubular isolating ycontact disposed in saidenclosing structure at one end of said xed conducting member andnormally in conducting relation to said fixed conducting member, saidisolating contact and said .xed conducting member forming an exhaustpath for fluid supplied to the end of said `conducting.; member remotefrom said isolating contact, and fluid-actuated rneans operable inresponse to a blast oi fluid supplied to said enclosing structureelectrically to separate said fixed conducting member and said isolatingoontact and to establish communication between the incoming fluid blastand the space within said tubular conducting member at the end thereofadjacent said isolating contact thereby to oppose the exhaust of fluidthrough said tubulai` conducting member.

4. An electric circuit breaker or" the fluidblast type comprising atubular enclosing structure, a fixed tubular conducting member disposedwithin said structure, a movable tubular isolating contact disposed inlspaced substantially coaxial relation to said fixed conducting member,fluid-actuated bridging means normally forming an electrical connectionbetween said conducting member and said isolating contact, saidisolating Contact and said fixed conducting member forming an exhaustpath for pressure fluid supplied to said enclosing structure and to theend of said fixed conducting member remote from said isolating contact,said fluid-actuated bridging means being operable in response to saidfluid to break the electrical lconnection between said fixed conductingmember and said isolating contact and to establish communication betweenthe incoming fluid blast and the space within said tubular conductingmember at the end thereof adjacent said isolating Contact thereby tooppose the exhaust of fluid through said tubular conducting member, andmeans for preventing the completion of an operation of saidfluid-actuated means until after openin--fr of said interruptingconta-ot means.

5. An electric circuit breaker of the duidblast type comprising atubular enclosing structure, a fixed tubular conducting member disposedwithin said structure, interrupting contact means biased towardengagement with one end of said fixed conducting member, a movabletubular isolating contact disposed at the other end of said fixedlconducting member in spaced substantially coaxial relation thereto,uidactuated bridging means normally forming an electrical connectionbetween said xed conducting member and said isolating contact, saidisolating Contact and said xed conducting member forming an exhaust pathfor fluid supplied to said interrupting contact means after operationthereof, said fluid-actuated bridging means being operable in responseto a blast of fluid supplied to said enclosing structure to break theelectrical connection between said xed conducting member and saidisolating con- 'tactl and to establish communication between theincoming iiuid blast and the space within said tubular conducting memberat the end thereof adjacent said isolating contact thereby to preventthe exhaust of liuid through said tubular conducting member, and meansfor pre- Venting the completion of an operation of said fluid-actuatedmeans until after opening of said interrupting contact means.

S. An electric circuit breaker oi the uidblast type comprising a tubularenclosing structure, a xed tubular conducting member disposed withinsaid structure, interrupting contact means biased toward engagement withone end of said xed conducting member, a movable tubular isolatingcontact disposed in said enclosing structure at the other end of saidxed conducting `member in spaced substantially colaxial relationthereto, bridging means normally forming an electrical connectionbetween said xed conducting .member and said isolating contact, saidisolating contact and said fixed conducting member forming an exhaustpath for fluid supplied to said interrupting Contact means afteroperation thereof, means including a. piston and a cylinder operable inresponse to a blast of fluid supplied te said enclosing structure tobreak the electrical connection between said ;fixed conducting memberand said isolating -contact and to establish communication between theincoming fluid blast and the space within said tubular conducting memberat the end thereof adjacent said isolating contact thereby to oppose theexhaust of iiuid thro-ugh said tubular conducting member, and

means including regulating valve means anording communication betweenatmosphere and the surface of said piston means opposite to the workingface thereof and a pcrt in a wall of said cylinder for admitting aportion of said blast to the surface of said piston opposite to theworking face thereof for preventing the completion lof an operation ofsaid fluid-actuated means until after opening of said interruptingcontact means.

7. A fluid blast electric circuit breaker comprising an enclosingstructure, a fixed tubular conducting member disposed within saidstructure, interrupting contact means disposed in said enclosingstructure and biased into engagement with said tubular conducting memberat .one extremity thereof, a tubular isolating contact disposed withinsaid enclosing structur in coaxial relation to said tubular contactmember at another extremity thereof and in spaced relation thereto, afluid-responsive bridging contact means normally interconnecting saidtubular conducting member and said isolating contact, said tubularconducting ymember and said tubular isolating contact forming a path forthe exhaust of fluid supplied to said interrupting contact after theinitiation thereby of opening movement of said interrupting contact andbefore disconnection of said isolating contact from said tubularconducting member by said huid-responsive bridging contact means inresponse to iuid supplied to said enclosing structure.

8. A fluid blast electric circuit breaker comprising an enclosingstructure, a fixed tubular 'conducting member disposed within saidstructure, interrupting contact means disposed in said enclosingstructure and biased into engagement with said tubular conducting memberat one extremity thereof, a tubular isolating contact disposed withinsaid enclosing structure in coaxial relation to said tubular contactmember at another extremity thereof and in spaced relation thereto, andduid-responsive bridging contact means normally interconnecting saidtubular conducting member and said isolating contact, said tubularconducting member and said tubular isolating contact forming a path forthe exhaust of iiuid supplied to said interrupting contact after theinitiation thereby of opening movement of said interrupting contact andbefore disccnnection of said isolating contact from said tubularconducting member by said fluid-responsive bridging contact means inresponse to iiuid supplied to said enclosing structure, fluid pressurein said tubular conducting member being substantially equalized afteroperation of said fluid-responsive bridging contact means so as tooppose the exhaust of fluid from said interrupting contact through saidtubular contact member.

HAROLD N. SCHNEIDER.

References Cited in the le of this patent UNITED STATES PATENTS NameDate Wilcox May 4, 1948 Latour Mar. 11, 1952 Number

